title: Cyclosporine attenuates arginine transport, in human endothelial cells, through modulation of cationic amino acid transporter-1.
abstract: BACKGROUND
  The spectrum of cardiovascular toxicity by cyclosporine (CsA) includes hypertension, accelerated atherosclerosis, and thrombotic microangiopathy, all of which are the result of endothelial cell dysfunction. Endothelial cell dysfunction is characterized by decreased endothelial nitric oxide synthase (eNOS) activity. Cationic amino acid transporter-1 (CAT-1) is the specific arginine transporter for eNOS. CsA has been shown to attenuate nitric oxide (NO) generation. However, the mechanism remains elusive. We hypothesize that CsA inhibits eNOS activity through modulation of its selective arginine supplier CAT-1.
  
  
  METHODS
  We studied the effect of CsA on arginine uptake, NO2/NO3 generation, and CAT-1, protein kinase Cα (PKCα), and phosphorylated PKCα protein expression in human umbilical vein endothelial cell cultures (HUVEC) in the absence and presence of L-arginine.
  
  
  RESULTS
  CsA (0.5-2 μg/ml) significantly attenuated arginine transport in a dose- and time-dependent manner, a phenomenon which was prevented by co-incubation with L-arginine (1 mM). The aforementioned findings were accompanied by increased protein nitration, a measure for peroxynitrite accumulation. In contrast, no changes were observed in NO2/NO3 generation. CsA significantly decreased the abundance of CAT-1 protein, an effect that was attenuated by L-arginine. PKCα and phosphorylated PKCα (CAT-1 inhibitors) protein contents were not affected by CsA.
  
  
  CONCLUSIONS
  CsA inhibits arginine transport and induces protein nitration in HUVEC through modulation of CAT-1.
authors.affiliation: Nephrology Department, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv, Israel.
authors.forename: Ayelet
authors.initials: A
authors.lastname: Grupper
authors.forename: Moshe
authors.initials: M
authors.lastname: Shashar
authors.forename: Dganit
authors.initials: D
authors.lastname: Bahry
authors.forename: Yael
authors.initials: Y
authors.lastname: Pri-Paz
authors.forename: Ohad
authors.initials: O
authors.lastname: Ben Tur
authors.forename: Sharon
authors.initials: S
authors.lastname: Levi
authors.forename: Tamara
authors.initials: T
authors.lastname: Chernichovski
authors.forename: Gil
authors.initials: G
authors.lastname: Chernin
authors.forename: Idit F
authors.initials: IF
authors.lastname: Schwartz
mesh_terms: D001120:Arginine / Q000187:drug effects* / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D027201:Cationic Amino Acid Transporter 1 / Q000187:drug effects* / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors*; D009573:Nitrites / Q000378:metabolism; D051571:Protein Kinase C-alpha / Q000187:drug effects / Q000378:metabolism
chemical_list: D027201:Cationic Amino Acid Transporter 1; D007166:Immunosuppressive Agents; D009566:Nitrates; D009573:Nitrites; C420825:SLC7A1 protein, human; D009569:Nitric Oxide; D016572:Cyclosporine; D001120:Arginine; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D051571:Protein Kinase C-alpha